Field of the Invention
The present invention relates to an inductive electric component, in particular an electric transformer, including a coil body which has contact pin strips integrally formed onto coil body flanges that define a winding space; a two-part magnet core having halves which can be pushed together on the coil body in such a way that they engage the coil body with center bosses and rest both on the coil body flanges and the contact pin strips; and a spring cap which can be slipped onto the magnet core located on the coil body for retaining the magnet core halves on the coil body, the cap having a yoke being concave at least in its middle region, legs on two opposite sides and spring hoops on two other opposite sides; wherein with the spring cap slipped on, the concave region engages the outside of the magnet core facing away from the contact pin strips, the legs rest on two opposite sides on outsides of the magnet core that are perpendicular to the contact pin strips, and the spring hoops engage two further opposite sides of the magnet core.
Such inductive components are known, for instance, from Siemens Data Book 1990/91, "Ferrite und Zubehor" [Ferrites and Accessories], particularly pp. 321-323 as well as 338 and 339.
One embodiment of a typical transformer model has a coil body and a so-called EP ferrite core, in the form of two core halves that can be mounted on the coil body. A further explanation thereof can be gathered from the description of the drawing, for the sake of simplicity. In such a device, a coil body has a winding space defined by two coil body flanges with a cylindrical through hole for receiving center bosses of EP core halves. The coil body also has two integrally formed-on contact pin strips with contact pins.
Two EP core halves with center bosses and core legs can be slipped onto the coil body in such a way that the center bosses engage the cylindrical through hole and the core legs are seated on the contact pin strips.
To that extent, the transformer model in question is generally known, and reference may be made, for instance, to the view shown on page 323 of the aforementioned Siemens Data Book.
In the known transformer model with an EP core, the core halves are held on the coil body by means of a retainer device that is formed by two separate parts, namely a hoop and a clamp. Both the hoop and the clamp are U-shaped in principle. The hoop has one detent protrusion on the outside of each of the two legs of the U-shaped element, while the clamp has one recess adapted to each of the detent protrusions of the hoop, on each of the legs of the U-shaped element.
The hoop and the clamp are each slipped from one side in the direction of the central axis of the through hole in the coil body and the center boss of the core halves onto the assembled unit including the coil body and the core halves, in the course of which the detent protrusions of the hoop then lock into place in the recesses in the clamps. Since the yoke of the clamp is constructed in such a way as to be concave and thus exerts an additional spring action, the core halves are pushed together in the direction of the aforementioned axis on the coil body and held. Moreover, the hoop seated on one core half has two legs being oriented inwardly and engaging the core half. They assure a certain retention at right angles to the aforementioned axis (which is also the magnetic axis of the transformer).
An embodiment of the type explained above is not completely satisfactory in terms of the retention of the core halves on the coil body. However, although the hoop and the clamp assure good retention in the direction of the magnetic axis, they do not always assure adequate retention at right angles to that axis, so that the core halves may still have a certain amount of play on the coil body, which can have a negative effect on the electromagnetic properties of the transformer.
Another known version of a typical transformer model has a so-called Q core, in the form of two core halves. With respect to the coil body and the ferrite core, this model generally matches the model with the EP core described above. In order to retain the two core halves on the coil body, a covering tab is provided, which is slipped from above onto this unit including the coil body and the core, with the core halves placed on the coil body. In the direction of the magnetic axis, the covering cap has two resilient legs on each of the opposite sides, and those legs engage the outsides of the core halves and press them together on the coil body in the direction of the magnetic axis. The problem addressed above of possibly inadequately fastening the core halves at right angles to the magnetic axis on the coil body still exists in that case.